The objective of the proposed research is to study at the biochemical level, the role of androgenic steroid hormones in development and regeneration of the hormone-sensitive levator ani muscle of the rat. The cytosolic androgen receptor will be investigated during normal development and during regeneration following crush injury or transplantation. In addition, we will study androgenic regulation of glucose 6-phosphate dehydrogenase, the rate-limiting enzyme in the pentose phosphate pathway. Muscle from normal rats and from mice with hereditary dystrophy will be employed. The anticipated results should enhance our knowledge of muscle growth and regeneration and may be applicable to treatment of human muscle malformations and neuromuscular disorders.